Please help me

I am a mom to a 11 month old baby girl, married for 4 years. my husband is a responsible, kind and loving guy. I always considered myself as a straight woman and yeah I did have a few crushes in my school and college days too. I fell in love with my husband and we got married. We waited till marriage to make love- Something we both agreed on. I thought it would be exciting the day we went on our honeymoon and I was really shocked that I wasn't getting turned on. My husband was kind enough to understand that may be I was just apprehensive and nervous as its our first time. But the truth is I wasn't feeling the desire or the lust I should feel for him. Eventually we both lost our virginity to eachother when we turned 28. Over the course of months I understood that though I had crushes, I never sexually fantasized about any guy/girl. 2 years into our marriage and my husband and I both wanted to be parents. It was the same about sex. No interest. I had sex only for my husband who loves me to the moon and back and I do too.. We had our little girl but.. Now I don't even feel like having sex, after the baby was born and my husband is also very busy with his new job working 12 hours a day. I started doing my search as to why I am this way. Found out that most of my feelings incline towards being asexual. I was shocked and now I feel like I am betraying my husband. I am not at all interested in sex or even pleasuring myself. I love my husband and my child more than anything in the world but the sex part is as if it doesn't exist in me. Please help me. How should I deal with it? Is there a way to change myself? My friends are on glow too and thats why I am keeping my identity hidden. I wanna save my marriage. 🙁